1. Field of the Invention
This invention relates to composite bearing assemblies for rotatable shafts and to methods of manufacturing such bearing assemblies. More specifically, the invention pertains to an annular bearing member having a plurality of arcuate segments that are made of different material with the segments being arranged circumferentially about a rotatable shaft for supporting the shaft.
2. Description of the Prior Art
Annular bearing members for supporting rotatable shafts concentrically within the bearing members have been made as solid rings and also have been made of, or split into, a plurality of segments that are assembled circumferentially about a shaft. Normally, the entire ring is made of one kind of suitable bearing material and bearing surfaces within the ring are accurately machine finished.
An arcuate pillow block bearing that extends through an arc of about 270.degree. with an opening at the top of the bearing is shown in U.S. Pat. No. 2,897,017 for rotatably supporting a shaft. The entire shaft load is supported by the lower portion of the bearing. U.S. Pat. No. 1,184,614 shows a semi-circular bearing plate that is open at the top and supports the lower half of a rotatable spool with the entire spool load being carried by the bearing plate. Pillow block bearings having lubrication chambers in the top portion of the bearing are shown in U.S. Pat. Nos. 890,735, 2,336,915 and 2,518,338.
U.S. Pat. No. 555,510 shows an outer race segment that extends through an arc of about 270.degree. for supporting anti-friction bearings. The remaining 90.degree. of arc, being located at the top of the outer race, is defined by a cover. A saddle supports the outer race segment and the only connection between the saddle and the cover is the outer race segment. U.S. Pat. No. 3,693,226 recognizes that significant savings in race material can be realized by using a small metal outer race facing a set of anti-friction bearings and being embedded in a plastic material that is less expensive than the metal outer race material.